الفهرس 
Marginal accuracy and internal fit of CAD/ CAM PEEK based and zirconia based monolithic single crowns
ContentsOnly 14 pages are availabe for public view
 |  | from | 97 |  |  |
| | | from | 97 | | |
Abstract
Non-metallic restorations are the most commonly desired among dentists and patients as it offers superior esthetics in terms of translucency, polychromacity and opalescence.Zirconia is a polycrystalline ceramic that was introduced in the dental fixed prosthodontics field as an alternative to long-span posterior ceramometallic FPDs. Moreover, it has higher mechanical properties than glass ceramics. However, zirconia is a brittle material with an elastic modulus of 205-210 GPa. Meawhile, it has high hardness, thus more likely to cause wear of the opposing dentition and rapid wear of the milling tools during construction as well as difficulties in repair if chipped or fractured. Moreover, zirconia lacks the etchable glass matrix and thus forms only a mechanical bond with the tooth substructure